Ventricles of the brain contain cerebral spinal fluid (CSF) that cushions the brain against shock. Cerebral spinal fluid is constantly being secreted and absorbed by the body. Cerebral spinal fluid is produced in the ventricles of the brain, where under normal conditions it is circulated in the subarachnoid space and reabsorbed into the bloodstream, predominantly via the arachnoids villi attached to the superior sagittal sinus. In a normal, healthy person, the secretion and absorption of cerebral spinal fluid is in equilibrium for the most part. However, if blockages of the circulation of cerebral spinal fluid are created, in the ventricles for example, cerebral spinal fluid can't be reabsorbed by the body at the proper rate and it can build up in the ventricles.
This can create a condition known as hydrocephalus which is marked by an excessive accumulation of fluid violating the cerebral ventricles and then the brain. Hydrocephalus is a condition characterized by abnormal flow, absorption, or formation of cerebral spinal fluid within the ventricles of the brain which subsequently increases the volume and pressure of the intracranial cavity. The condition can cause a separation of the cranial bones. If left untreated, the increased intracranial pressure can lead to neurological damage and may result in death.
Over the past 40 years, a common treatment for hydrocephalus patients has been to implant a cerebral spinal fluid shunt. The standard shunt consists of a ventricular catheter, a valve and a distal catheter. The ventricular catheter is tunneled into the brain through a burr hole in the skull and placed into ventricles to shunt cerebral spinal fluid to other areas of the body. The excess cerebral spinal fluid is typically passively drained from the ventricles to a suitable cavity, for example the peritoneum or the atrium, where it can be reabsorbed. The shunt relieves the pressure from the cerebral spinal fluid on the brain, thereby lessening or managing the symptoms.
Current cerebral spinal fluid shunts all act in a passive manner, which provides only approximate control of cerebral spinal fluid drainage pressure and volume. More accurate control of cerebral spinal fluid drainage could alleviate symptoms of shunted patients and assist in the management of hydrocephalus.